Gun mounting for machine guns adapted to recoil



July 15, 1941. R. BRAUN 'ETA'.

GUN MOUNTING FOR MACHINE GUNS ADAPTED TO RECOIL 2 Sheets-Sheet 1 Filed Oct. 25, 14957 July 15, 1941. R BRAUN ETAL 2,249,310

GUN MOUNTING FOR MACHINE GUNS ADAPTEGTO RECOIL Filed Oct. 25, 1937 2 Sheets-Sheet 2 In V672 fo rs.'

, returned into 'firing position.

Patented July-15, 1941 .GI-JN MOUNTING FOR MACHINE GUNS ADAPTEDIO RECOIL Richard Braun and Heinrich Herlach, Berlin- Frohnau, Germany, assigner: to Rheinmetall- .Borsig Aktiengesellschaft, Dusseldorf, Germaxmacorporation or Germany Application October 25. 1937,1 Seriall No. 170,876

. In Germany October. 31, 1934 l 5 Claims. In order that precision oi.' fire may be increased.

mounted machine guns have, according to a recent practice, been arranged to recoil on the,

gun mounting. This insures steadiness of the gun mounting during firing. It was recognised however. that each shot in a series should be red as far as possible under like conditions, and particularly with one and the same longitudinal position of the gun on the gun mounting and that butler and running-out devices should have'as far as possible an equal and impact-free action.

Attempts have hitherto been made to obtainthose conditions by constructing the firing devices so that they, after :tiring the nrst shot, are prevented from again firing the gun until it has tion however, the lgun, in order to avoid injurious impact, should return into its normal, initial or iiring position with reduced speed and only after the recoil force had been overcome and this resuited in a serious decrease in the speed of nre. n the other hand higher firing-speeds were attained with an arrangement in which the gun was supported in a floating, intermediate position between two sets of opposing springs, one of which served as a recoil-braking device, and the second operated as acounter recoil braking device at the end of the running home or return movement of the gun. In this latter arrangethe second and each subsequent shot in aseries and produces an early-detonation effect as occurs in guns of the type having a recoiiing barrel, and

In such construc- Aas thus, is able to utilize the running-.out energy of 4 the gun in order to dissipate the subsequent recoil energy. But the requirement that there should V be the same conditions for each individual shot gun. Accordingly the recoil was taken up at the drst round fired by the recoil butter device alone,

but thereafter with the assistance of theabsorbing effect of any available running-out energy.

It is hardly possible by such arrangement to obtain a constant ring position forthe gun on the mounting. and this isparticularly so in the case of large-calibre machine guns, and-the considerable deviations from the first firing position impairing the accuracy o f lire.

In order to attain high-precision of me, the

main Object of the inventionistherefore topro-v builer device for the slide 1;A in the form of a 4 cure uniform firing positions of the gun on its mounting, and also of the movement of the gun, when each shot is iired. The attainment of such conditions. diminishes to a certain extent the A, reduction in the speed of fire of machine guns which are movabiy carried on their mountings as compared with the speed attainable when the guns are lrigidly mounted. In a gun subjected to -the action of oppositely operating springs according to the present invention and wherein the recoil energy is absorbed by running-out energy,

the nring of the ilxst and every subsequent shot is controlled according to the position' of the gun on thegun-mounting. Before each shot is fired the gun is in a rear cocked-position on the gun mounting, and moves forward from this position in order to be fired. The gun is fired when it reaches a certain position during this forward movement. by the action of a member of the gunmounting acting on the trigger of the gun. 'Ihen the recoil energy generated when the shot is fired is absorbed partially by the available runningout energy of the gun. while leaving a reserve of energy which sufilces to return the gun to its initial position in preparation for the nextl shot.

Thus, with only small braking forces, the path of recoil of the gun is short, theoperation is substantially completely free from lars. and its speed of firing is to no appreciable extent inferior to in which;

Fig. 1 shows .a side elevation of the mounted gun, the essential parts being in section,

Fig. 2 is a partial crosssection along" the line 1. II-II 0f Fig. 1,

Fig. 3 shows, on'an enlarged scale', a sectional plan 0f the firing device along the line III-'III of Fig. 1,

Fig. 4 shows, in sectional elevation, an additional running-out buffer-device in the form of a spring brakeyand Figs. 5-7 show fragmentary sectional views of a modification of the buii'er device in theform of a hydraulic brake. l

The gun a. which may for example be a machine gunof 3.7 cm. caliber, is carried on the gun mounting by a slide 'b -which in turn is .-mounted for longitudinal displacement on a cradlemember d having'bore di, which serves as a guide;4 In this. upper longitudinal bore di of the cradle member d there areenclosed the recoil buier spring f together with a front buffer spring g. '.Ihese springs act in opposite direc-- tions on the slide b by way of displaceable abutment washers f1 or g1 at either side of the intermediately disposed xed collar hr on a piston rod h. which is bolted at bsto the slide b. An abutment d2 in the bore d1 having an opening of approximately the same diameter as the collar 'hi of the piston rod h limits the forward movement of the Washer f1 of the recoil spring f and also the rearward movement of the washer gi of the buffer spring g and the arrangement is such that only one of thetwo springs f and g acts .on the spring bar h at a time. and in their action they therefore. cannot mutually overcome the action of each other. 'Ihe rear washer ,fz of the recoil spring f is displaceable and adapted to be adjusted, by'means of a link Ic which is connected to the lower gun mounting i' eccentrically to the trunnion da, in dependence ori the elevation of the gun barrel, in such a manner that by an increase or decrease in spring compression, the weight component of the gun and its slide b which may be resolved in the direction of recoil of the gun, is. compensated for.

An arm d4 on the cradle d (see Figs. 1 and 3) projects upwardly at the side vof the gun and carries on a bar d5 a springactuated tiring nnger l which protrudes into the path of a` trigger actuating member ai of the gun. which member in the form illustrated in the drawings projects from a bearing pin ai. The firing finger l, on its supported bar d5 is adapted to move out of the path of the trigger actuating member az against the action Aof a spring, in order, when the gun recols, to allow the latter to pass by uninfluenced. In order that the tiring position may be ilxed as desired, the bar ds is made adjustable in the directionof the -path of movement of the gun..

` tion. Otherwise the described cycle of operations under the influence of the recoil spring f, again runs forward. Thus the result is obtained that also for the shots following the nrst one in continuous fire, at the moment when the gun trigger az is innuenced, there is always one and the same condition of movement and speed. As a precaution, the recoil of the gun beyond the arresting position provided by the locking device de, may also be limited by a buffer b2, preferably of rubber and mounted, for example, at the front end of the slide b and arranged to strike against the front face of the cradle d.

Unavoidable differences in the recoil energy give iise to diliierent speeds at the moment when the trigger is released and at the moment when drawn back on the cradle d into the rear cocked position, where it is held-,firmly by the trigger plate de of the cradle d engaging .the notch bi in the slide b. The' recoil spring f is thus compressed andthe actuating member or plunger a: passed to the rear of the ilring finger lof-the cradle d.

In order to re the-gun the slide b is released by moving the retaining member or trigger plate de; whereupon'the gun a with .the slide b quickly moves forwardactuated by the recoil spring l. -When it reaches the ring ilnger l Vthe plunger a2 is pressed inwards and the firing lmechanism ofwhich nrst sets the slidable parts inside the gun mechanism inmotion, is able to act 'upon the gun and its slide b 'as a whole, and afterdissipating the stored energy. with its remaining force, partly aided by the spring a, throws the gun a and the slide b back intothe initial positionthus compressing 'the recoil spring f. If then lthe trigger plate 'da is moved back into the path oi' the slide b for interrupting iire, the slide the projectile leaves the gun. Such irregular conditions impairing the accuracy of re may be due to difference in ammunition and process of combustion and also to varying frictional conditions, in spite of 'the release of the gun trigger a2 which takes place with the gun always in the same position. y

According to the invention there is also provided an additional buier device m which has an equalising effect on the recoil and counterrecoil movements ofthe gun, which obviates at the outset vany diierences between the speed of 4one running-out movement and the others due to the circumstances explained above. This damping device may be xed at the front end of the cradle member d, but could also be incorporated in the device f, d1. The additional builer device acts only at the beginning and at the iirst part of a recoil movement of the gun. For this purpose as shown in Fig. l and on an enlarged scale Y carrying a pivotal catch ma, sopas to be displaceis arrested and held fast in the rear cocked posiin Fig. 4, there is mounted in a buier casing mi which is secured to the cradle d, a'plunger ma able forwardly against the action of-a pre-ten- .sioned spring m4. A plunger rod ma which protrudes through the front end wall of the casing', limits by means of an abutment formed by the nuts me in commotion with a flexible washer jected to a damping force'whichmoderates or eliminates any speed irregularities. After recoiling a certain distance, the end of the catch ma enters under a control ring 1m placed around the buffer m, thus being moved out of the path of the slide lug ba. whereupon the further forward movement of the gunl is effected solely by the action of the running out spring f. 'I'he plunger ma with the catch ma returns into its rear initial position and is ready to come into operation again the next time the gun recoils. The fact that the control ring mais adapted to be displaced on the casing 'mimalres it possible to modify as desired the duration and magnitude of the force exerted by the buier while by means of the nuts me on the plunger rod ms thelength vof the stroke of the plunger can be adjusted.

A device which is more advantageous thanthe spring buer shownin Fig. 4 is the hydraulic device shown in Figs. 5 to 7. In this case the projecting lug b3 is in firm and constant connection witlna plunger rod. ns which controls a hollow plunger m fixed thereon and which reciproca/tes in `the hydraulic cylinder 1u. During a. definite portion of the recoil of the slide b on the cradle d (Fig. l), the fron-twali of the plunger m which is provided with an enlarged bore 11.9

moves over a collar moon the inwardly prolonged cylinder cover'nn fittingclosely therein so as to make a seal at this point. The liquid from the front end of -the piston is thereby forcedto the lrear of 'the piston through a narrow bypass ma which is adapted to be throttled .by means of an adjusting screw nu. Thus the-recoil of, the `gun is opposed by a damping force the magnitude of which may be controlled by means of the throttle screw 11.12 and which, depending on the actual recoil-speed at-any time automatically, controls and checks any undesired lexcess of speed. The conical shape of the collar me ensures lthat the -damping force is produced smoothly without jar. In order to eliminate any braking effect. when the vgun reoils there is provided as shown in Fig. v'1 a second liquid by-pass m4 which, when the plunger bore n passes over the collar nm. causes the liquid behind the plunger to flow 'unthrottled into the free space infront of the plunger. .A non-return valve ma thencloses the' bore m14 in order to prevent liquid from passing in the reverse direction when the gun runs out.

2. An autom-atie gun and carriage in whichit is recoilably mounted comprising means on the carriage for firing the gun during its forward run-out movement, arecoil and run-out spring and a buer spring operative on said gun in opposite directions, a brake device'co-operating wi-th a recoiling part of the gunin said run-cut movement, means in said brake device limiting effective Braking action to a restricted range in said movement, co-acting stop means on said brake device and the recoiling part and means for adjustingthe stop means on the brake'device to time said range-of eiective braking action with respect to the firing means.

3. An automatic gun and carriagein which it is recoilably mounted, comprising means on the carriage for firing the gun during its forward the first pa-rt of its forward run-out movement,V

. said brake means including abuffer piston carrying means temporarily engaged by a recoiling part of the gun during the forward run thereof, and means for adjustingthe range of such engagement.

4. 'An automatic gunvand caniage in which it The throttling control oithe damping force can also be utilized advantageously in order to change the speed of nre, while the adiustability of the point of engagement of .the slide lug b3v with the 'plunger rod ns1-anders it possible to adjust the range oi' action 'of the deviceduring the running out of the gun.

'wherebythe first shot of a series after release Having now particularly described and ascerand a buirer spring operative on said'gur'l in opposite directions, means for retaining the gun 'under `the tension of said vrun-out spring in .a position i rearward oi' norm-al forward position whereby the first shot of a series after release of the gun by said retaining means wm be med by said n-ring' means under conditions-of gun movementsimilar to those of succeeding shots of the series, and

brake means operative upon the gun only during the first part of its forward run-out movement and including a member .temporarily engaged byl a recoiling part of the gun during the'forward run' thereof. and means for adjusting the range of such engagement.

' .tion thereof.

is recoilably mounted comprising means on the carriage for firing the gun during its forward run-out movement,4 a recoil and run-out spring and a buffer spring opera-tive on said gun in opposite directions, means for retaining the gun under the tension'of. said run-out spring in a position rearward .of normal forward position of ..the gun by said retaining means will be fired by said ring means under ,conditions of gun movement similar to those 'of succeeding shots of the series, and brake means operative upon the gun only during the first *part of its for ward run-out movement and including a mem- 4bei' temporarily engaged by a 'reooiling part of.

the gun during the forward run thereof.

5. An automatic gun and carriage in which it is recoilably mounted, including means on the carriage for firing the gun during its vforward -run-out movement, a recoil and run-out spring and a buffer spring operative on said gun in opposite'directions, a spring brake device adapted to equalize the velociti of individual run-,out movement of a recalling part of the gun and including'means for timing its action on the recoiling part of .the gun, and a stop member-.adjustable on said brake device for timing tlie ac- RICHARDBRAUN. Emmen .mamon 

